Six cavity building block



FIG. 1 is a perspective view of a six cavity building block showing our new design;

FIG. 2 is an end elevational view thereof, the other end being a mirror image thereof.

FIG. 3 is a top plan view thereof.

FIG. 4 is a bottom plan view thereof.

FIG. 5 is a side elevational view thereof, the other side being a mirror image thereof. 

The ornamental design for a six cavity building block, as shown and described. 